The present invention relates to the construction of corners for structural members made of fiber reinforced material, and which are formed by four surfaces arranged at angles with respect to each other that converge to form the corner.
Boxes, frames, flanges or other structural members which are made by laminating materials have corners which are formed by overlapping the laminations. Shoulders, bulges, steps and recesses which result from overlapping the laminations cause interference when several corners are fitted into each other are joined together. In addition, overlapping the laminations increases the weight of the corners and interferes with the flux pattern or path of forces within the structural member. It is also desirable that the fibers of the fiber reinforced materials form well defined fiber patterns and symmetrical patterns between the layers. This will ensure that the various parts made from the fiber reinforced materials will retain their shape during a hardening process. This requirement cannot be easily met when structural members are formed by overlapping laminations because stresses and deformations are likely to occur in the thickened areas of the overlapped laminations when the members cool after a hardening process at an elevated temperature. In structural members which have corners or other areas made of overlapped laminations, it is necessary to use more layers of the fiber material, to avoid the undesirable stresses and deformations, than are normally required for the strength of the member.
It is accordingly an object of the present invention to provide corners of structural elements made of fiber reinforced materials which avoid the disadvantages of corners made by overlapping laminations.
A more specific object of the present invention is to provide a construction for the corners of structural members made of fiber reinforced materials which have absolutely smooth surfaces and uniform wall thicknesses while still making the best use of the properties of the fiber reinforced material.
Other objects, features and advantages of the present invention will become more apparent from the description of the invention in connection with the annexed drawings to be described more fully hereinafter.